pixelscan

The pixelscan library provides functions to scan pixels on a grid in a variety of spatial patterns. The library consists of scan generators and coordinate transformations. Scan generators are Python generators that return pixel coordinates in a particular spatial pattern. Coordinate transformations are iterators that apply spatial transformations to the coordinates created by the scan generators. Transformation can be chained to yield very generic transformations.

Usage

The typical calling syntax is

for x, y in transformation(generator(...), ...):
   foo(x,y)

For example, the following scans pixels in a clockwise circular pattern from the origin up to a radius of 1

for x, y in circlescan(0, 0, 0, 1):
   print x, y

and will generate the following points

(0,0), (0,1), (1,1), (1,0), (1,-1), (0,-1), (-1,-1), (-1,0), (-1,1)

To skip every other pixel a skip transformation can be applied

for x, y in skip(circlescan(0, 0, 0, 1), step=2):
   print x, y

which will generate the following points

(0,0), (1,1), (1,-1), (-1,-1), (-1,1)

Scan Generators

The following are the currently available generators

Name	Description
circlescan	Generates pixels in a clockwise circular pattern
gridscan	Generates pixels in rectangular grid pattern
ringscan	Generates pixels in a ring pattern (squares or diamonds)
snakecan	Generates pixels in a snake pattern along the x then y axis
walkscan	Generates pixels in a random pattern using a random walk

Coordinate Transformations

The following are the currently available transformations

Name	Description
clip	Clips the coordinates at the given boundary
reflection	Reflects the coordinates along the x and/or y axis
reservoir	Randomly samples the pixels using reservoir sampling
rotation	Rotates the coordinates about the origin counter-clockwise
sample	Randomly samples the pixels with a given probability
scale	Scales the coordinates with a given scale factors
skip	Skips the pixels with the given step size
snap	Snap the x and y coordinates to a grid point
swap	Swap the x and y coordinates
translation	Translates the coordinates by the given offsets

Warnings

Transformations such as the rotation can yield non-grid points. They can be snapped to a grid point using the snap transformation.

Changelog

• v0.3.2

  • Fix deployment token

• v0.3.1

  • Fix pypi deployment twine bug

• v0.3.0

  • Switch coverage to coveralls
  • Clean up code health issues
  • Fix landscape syntax
  • Add health and version badges
  • Fix pylint options syntax
  • Replace link table with badge links

• v0.2.0

  • Add clip transformation
  • Add random walk generator
  • Replace random generators with reservoir transformation
  • Add continous integration and testing
  • Add automated deployment

• v0.1.0

  • Initial release